JAVA文件名工具类-扩展名、文件夹、文件等判断

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package com.wesley.framework.commen.io;

import java.io.File;

import org.apache.commons.lang.StringUtils;

/**
 * @author it.zl
 * 
 */
public class PathUtil {

	public static final String DOT = ".";
	public static final String SLASH_ONE = "/";
	public static final String SLASH_TWO = "\\";

	/**
	 * 获取没有扩展名的文件名
	 * 
	 * @param fileName
	 * @return
	 */
	public static String getWithoutExtension(String fileName) {
		String ext = StringUtils.substring(fileName, 0,
				StringUtils.lastIndexOf(fileName, DOT));
		return StringUtils.trimToEmpty(ext);
	}

	/**
	 * 获取扩展名
	 * 
	 * @param fileName
	 * @return
	 */
	public static String getExtension(String fileName) {
		if (StringUtils.INDEX_NOT_FOUND == StringUtils.indexOf(fileName, DOT))
			return StringUtils.EMPTY;
		String ext = StringUtils.substring(fileName,
				StringUtils.lastIndexOf(fileName, DOT));
		return StringUtils.trimToEmpty(ext);
	}

	/**
	 * 判断是否同为扩展名
	 * 
	 * @param fileName
	 * @param ext
	 * @return
	 */
	public static boolean isExtension(String fileName, String ext) {
		return StringUtils.equalsIgnoreCase(getExtension(fileName), ext);
	}

	/**
	 * 判断是否存在扩展名
	 * 
	 * @param fileName
	 * @return
	 */
	public static boolean hasExtension(String fileName) {
		return !isExtension(fileName, StringUtils.EMPTY);
	}

	/**
	 * 得到正确的扩展名
	 * 
	 * @param ext
	 * @return
	 */
	public static String trimExtension(String ext) {
		return getExtension(DOT + ext);
	}

	/**
	 * 向path中填充扩展名(如果没有或不同的话)
	 * 
	 * @param fileName
	 * @param ext
	 * @return
	 */
	public static String fillExtension(String fileName, String ext) {
		fileName = replacePath(fileName + DOT);
		ext = trimExtension(ext);
		if (!hasExtension(fileName)) {
			return fileName + getExtension(ext);
		}
		if (!isExtension(fileName, ext)) {
			return getWithoutExtension(fileName) + getExtension(ext);
		}
		return fileName;
	}

	/**
	 * 判断是否是文件PATH
	 * 
	 * @param fileName
	 * @return
	 */
	public static boolean isFile(String fileName) {
		return hasExtension(fileName);
	}

	/**
	 * 判断是否是文件夹PATH
	 * 
	 * @param fileName
	 * @return
	 */
	public static boolean isFolder(String fileName) {
		return !hasExtension(fileName);
	}

	public static String replacePath(String path) {
		return StringUtils.replace(StringUtils.trimToEmpty(path), SLASH_ONE,
				SLASH_TWO);
	}

	/**
	 * 链接PATH前处理
	 * 
	 * @param path
	 * @return
	 */
	public static String trimLeftPath(String path) {
		if (isFile(path))
			return path;
		path = replacePath(path);
		String top = StringUtils.left(path, 1);
		if (StringUtils.equalsIgnoreCase(SLASH_TWO, top))
			return StringUtils.substring(path, 1);
		return path;
	}

	/**
	 * 链接PATH后处理
	 * 
	 * @param path
	 * @return
	 */
	public static String trimRightPath(String path) {
		if (isFile(path))
			return path;
		path = replacePath(path);
		String bottom = StringUtils.right(path, 1);
		if (StringUtils.equalsIgnoreCase(SLASH_TWO, bottom))
			return StringUtils.substring(path, 0, path.length() - 2);
		return path + SLASH_TWO;
	}

	/**
	 * 链接PATH前后处理，得到准确的链接PATH
	 * 
	 * @param path
	 * @return
	 */
	public static String trimPath(String path) {
		path = StringUtils.replace(StringUtils.trimToEmpty(path), SLASH_ONE,
				SLASH_TWO);
		path = trimLeftPath(path);
		path = trimRightPath(path);
		return path;
	}

	/**
	 * 通过数组完整链接PATH
	 * 
	 * @param paths
	 * @return
	 */
	public static String bulidFullPath(String... paths) {
		StringBuffer sb = new StringBuffer();
		for (String path : paths) {
			sb.append(trimPath(path));
		}
		return sb.toString();
	}

	public static void main(String[] args) {
		String fileName = "D:/apache-tomcat-7.0.23/webapps/ROOT/report rets/attachment/report/test/";
		System.out.println(PathUtil.fillExtension(fileName, "PDF"));
		System.out.println(new File(fileName).getPath());
		String[] paths = { "win", "t", "a", "teswe.te" };
		System.out.println(PathUtil.bulidFullPath(paths));
	}
}